HR: 0830h
AN: OS21B-1129    [PDF]
TI: Dynamical Nonlinearity in the Atmospheric Response to Atlantic Sea Surface Temperature Anomalies
AU: * Robinson, W A
EM: robinson@atmos.uiuc.edu
AF: Department of Atmospheric Sciences University of Illinois at Urbana-Champaign, 105 South Gregory Street, Urbana, IL 61801 United States
AU: Li, S
EM: shuanglin.li@noaa.gov
AF: NOAA-CIRES Climate Diagnostics Center, R/CDC1 325 Broadway, Boulder, CO 80305-3328 United States
AU: Peng, S
EM: Shiling.Peng@noaa.gov
AF: NOAA-CIRES Climate Diagnostics Center, R/CDC1 325 Broadway, Boulder, CO 80305-3328 United States
AB: Large ensembles (100 members) of atmospheric general circulation model experiments are forced throughout the Northern Hemisphere cold season by four different sea surface temperature (SST) fields: the observed climatology, the so-called SST tripole pattern, and its subcomponents. Late winter responses to the component anomalies are of modest amplitude but are, because of the large ensemble size, significant. Despite their modest amplitudes, the responses display additive nonlinearity, in that the sum of the separate responses to the component anomalies differs significantly from the response to the tripole. Neither the heating field nor the basin averaged zonal winds display this nonlinearity. It is most evident in a sub-basin scale wave train, and most significant in its impact on the amplitude of the geopotential response. These results indicate that even for modest forcing, responses to patterns of SST anomalies cannot necessarily be understood as the sums of responses to constituent anomalies.
DE: 3309 Climatology (1620)
DE: 3339 Ocean/atmosphere interactions (0312, 4504)
DE: 4215 Climate and interannual variability (3309)
SC: Ocean Sciences [OS]
MN: 2003 Fall Meeting